Printers and MFPs using electrophotographic image forming apparatus have been required to consider the environment recently, e.g., trials to decrease power consumption of the printers and MFPs to reduce CO2 and use biomass materials to close to carbon neutral are made. Under the circumstance, a toner for electrophotography is required to lower its fixable temperature, e.g., as a binder resin used in the toner, a crystalline resin instantly melting when heated to be fixed, typified by a crystalline polyester resin is known.
However, toners using a crystalline resin are likely to agglutinate with each other in an image developer, resulting in deterioration of image quality. It is thought this is because the crystalline resin is softer than an amorphous resin used in conventional toners and locally deformed due to mechanical stress.
Further, a toner using the crystalline resin as a main component is easily fell out after fixed when scraped with a pencil. It is thought this is because the crystalline resin has low mechanical strength as well.
Japanese published unexamined application No. 2010-77419 discloses a crystalline resin having a specific storage elastic modulus and a loss elastic modulus for the purpose of providing a particulate resin having good low-temperature fixability and anti-blocking capability. Further, a block resin formed of crystalline polyester and amorphous polyurethane is disclosed as a crystalline resin.
However, toners using the crystalline resin still agglutinate with each other and images after fixed still have low mechanical strength.
Because of these reasons, a need exist for a toner using a crystalline resin, which prevents the toners from agglutinating with each other in an image developer and improves image strength after fixed.